Goosebumps

Let's start with the pimples and their purpose. What are they good for? We can shed some light on the problem by looking at the heebie-jeebie incidents.

When we feel chilly.

When someone runs his fingers through our hair.

When we listen to certain music.

Gooseflesh makes our hair stand on end, an evolutionary heritage. To create an air cushion against the cold, or to enable the one who is grooming us to find the fleas. Not that we humans have that much fur anymore, but evolution is slow.

Why with music then? Wait, we are not there yet. There is a third hair-raising scenario, observable in cats...

... and owls:

It's to appear "larger than life". To look as impressive and threatening as possible.

Humans are a social species; our best and our worst surfaces when we act in groups. The most dangerous thing on earth may be a group of angry men, about to fight another group of angry men.

When is a fighting group most effective? When its members act in a synchronised way. And the more effective the group is, the safer its members are. Thus, from an evolutionary viewpoint, it should feel good to get synchronised. And it does. Watch these videos. You may not like all of them... but they have a leitmotif.

There appears to be a connection between our "war genes" and our love for music. Does that devalue anything? Not at all. If we recognise our evolutionary legacy, we can tap into its mechanisms for our own pleasure. And we are also able to realise the instances when group synchronisation starts to become dangerous.